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question_answer1) Why do bodies of small mass require small initial effort to bring them into motion?
question_answer2) Can a body in linear motion be in equilibrium?
question_answer3) A body is acted upon by a number of external forces. Can it remain at rest?
question_answer4) If the net force acting on the body be zero, will the body remain necessarily in rest position? Explain your answer.
question_answer5) If a force is acting on a moving body perpendicular to the direction of motion, then what will be its effect on the speed and direction of the body?
question_answer6) Why do the passengers fall in backward direction when a bus suddenly starts moving from the rest position?
question_answer7) Why are passengers thrown forward from their seats when a speeding bus stops suddenly?
question_answer8) A man jumping out of a moving train falls with his head forward. Why?
question_answer9) Why do the blades of an electric fan continue to rotate for some time after the current is switched off?
question_answer10) A stone when thrown on a glass window smashes the windowpane to pieces, but a bullet from the gun passes through making a clean hole. Why?
question_answer11) We beat a blanket with stick to remove dust particles. Why?
question_answer12) If you jerk a piece of a paper placed under a book very quickly, the book will not move. Why?
question_answer13) Why fruits fall down from a tree, when its branches are shaken?
question_answer14) Why an athlete runs some steps before taking a jump?
question_answer15) A passenger sitting in a carriage at rest pushes it from within. Will the carriage move?
question_answer16) If a ball is thrown up in a moving train, it comes back to the person's hands. Why?
question_answer17) Why are the passengers thrown out- wards when a car in which they are travelling suddenly takes a circular turn?
question_answer18) Why are the wheels of vehicles are provided with mudguards?
question_answer19) An astronaut accidentally gets thrown out of his small spaceship accelerating in inter-stellar space at a constant rate of\[\mathbf{100}\text{ }\mathbf{m}{{\mathbf{s}}^{\mathbf{-2}}}\]. What is the acceleration of the astronaut the instant after he is outside the spaceship?
question_answer20) Why is Newton's first law of motion also called law of inertia?
question_answer21) A thief jumps from the upper storey of a house with a load on his back. What is the force of the load on his back when the thief is in air?
question_answer22) A soda-water bottle is falling freely. Will the bubbles of the gas rise in the water of the bottle?
question_answer23) A bird is sitting on the floor of a wire cage and the cage is in the hand of a boy. The bird starts flying in the cage. Will the boy experience any change in the weight of the cage?
question_answer24) The distance travelled by a body is directly proportional to time. Is any external force acting on it?
question_answer25) Chinawares are wrapped in straw paper before packing. Why?
question_answer26) Why we are hurt less when we jump on a muddy floor in comparison to a hard floor?
question_answer27) Why are shockers used in cars, scooters and motorcycles?
question_answer28) Why buffers are provided between the bogies of a railway train?
question_answer29) Why is it necessary to bend knees while jumping from greater height?
question_answer30) A brick can be pushed gently on the smooth floor by applying force with our foot. But if we kick the brick, the foot is hurt. Why?
question_answer31) Why is it that when a man jumps down from a height of several storeys into a stretched trapaulin, he receives no injury?
question_answer32) According to Newton's third law, every force is accompanied by equal and opposite force. How can anything move then?
question_answer33) Why is it difficult to drive a nail into a wooden block without supporting it?
question_answer34) Why it is difficult to climb up a greesy pole?
question_answer35) In a tug of war, the team that pushes harder against the ground wins. Why?
question_answer36) Can a sailboat be propelled by air blown at the sails from a fan attached to the boat?
question_answer37) A man is at rest in the middle of a pond on perfectly frictionless ice. How can he get himself to the shore?
question_answer38) Two bodies of masses M and m are allowed to fall from the same height. If the air-resistance be same for each body, will the two bodies reach the earth simultaneously?
question_answer39) There is some water in a beaker placed on the pan of a spring balance. If we dip our finger in this water without touching the bottom of the beaker then what would be the effect on the reading of the balance?
question_answer40) Two boys having the same mass are standing on ice-skates at some distance apart on a friction- less surface. A rope is fastened around the body of a boy, the other end of which is in the hand of the second boy. What would happen if the second boy pulls the rope?
question_answer41) A retarding force is applied to stop a motor car. If the speed of the motor car is doubled, how much more distance will it cover before stopping under the same retarding force?
question_answer42) Why does a rifle give a backward kick on firing a bullet?
question_answer43) Why is it advisable to hold a gun tight to one's shoulder when it is being fired?
question_answer44) When a body falls to the earth, the earth also moves up to meet it. But the earth's motion is not noticeable. Why?
question_answer45) A meteorite bums in the atmosphere before it reaches the earth's surface. What happens to its momentum?
question_answer46) Why does a heavy rifle not kick as strongly as a light rifle using the same cartridge?
question_answer47) Why is static friction called a self adjusting force?
question_answer48) Can we get off a frictionless horizontal surface by jumping?
question_answer49) Automobile tyres are generally provided with irregular projections over their surfaces. Why?
question_answer50) Carts with rubber tyres are easier to fly than those with iron wheels. Why?
question_answer51) Sand is thrown on tracks covered with snow. Why?
question_answer52) Why are wheels of automobiles made circular?
question_answer53) Proper inflation of tyres of vehicles saves fuel. Why?
question_answer54) It is difficult to move a cycle along a road with its brakes on. Explain?
question_answer55) A large size brake on bicycle is as effective as small one. Comment.
question_answer56) Why is it difficult to put a cycle into motion than to maintain its motion?
question_answer57) How does friction help us in walking?
question_answer58) Why do we slip on a rainy day?
question_answer59) Why is it difficult to walk on sand?
question_answer60) Why fictional force gets increased when a surface is polished beyond a certain limit?
question_answer61) When a person walks on a rough surface, the frictional force exerted by the surface on the person is opposite to direction of his motion. State whether it true or false?
question_answer62) Why has a horse to pull a cart harder during the first few steps of his motion? Or A horse has to apply more force to start a cart than to keep it moving. Why?
question_answer63) Is it unreasonable to expect the coefficient of friction to exceed unity?
question_answer64) Is friction a non-conservative force?
question_answer65) For uniform circular motion, does the direction of centripetal force depend on the sense of rotation?
question_answer66) A stone tied at the end of a string is whirled in a circle. When the string breaks, the stoneflies away tangentially? Explain why.
question_answer67) Why does a child in a merry-go-round press the side of his seat radially outward?
question_answer68) Why does skidding takes place generally on a rainy day along a curved path?
question_answer69) A car is taking a sudden turn to the left. A passenger in the front seat finds himself sliding towards the door. Explain, indicating the forces acting on the passenger and the car at this instant.
question_answer70) The outer rail of a curved railway track is generally raised over the inner. Why?
question_answer71) A motor cyclist is going in a vertical circle. What is the necessary condition so that he may not fall down?
question_answer72) A bucket containing water is rotated in a vertical circle. Explain, why the water does not fall.
question_answer73) Why does a pilot looping a vertical loop lot fall down even at the highest point?
question_answer74) What is the maximum possible velocity at the lowest position for oscillation of a simple pendulum of length L. What can happen to the motion if the velocity exceeds this value?
question_answer75) A cricket player lowers his hands to catch the ball safely. Explain, why?
question_answer76) It is easy to catch a table tennis ball than a cricket ball even both are moving with same velocity. Why?
question_answer77) Why does a cyclist bend inwards while riding along a curved road?
question_answer78) The motion of a particle of mass m is described by \[y=ut+1/2g{{t}^{2}}\]Find the force acting on the particle.
question_answer79) A particle of mass 0.3 kg is subjected to a force of \[F=-kx\]with\[k=15N{{m}^{-1}}\]. What will be its initial acceleration, if it is released from a point 20 cm away from the origin?
question_answer80) A block of mass M is pulled along a horizontal frictionless surface by a rope of mass m. A force P is applied at the free end of the rope. Find the force exerted by the rope on the block.
question_answer81) Three forces \[{{F}_{1}},{{F}_{2}}\]and \[{{F}_{3}}\] are acting on a particle of mass m, such that \[{{F}_{2}}\] and \[{{F}_{3}}\] are mutually perpendicular and under their effect, the particle remains stationary. What will be the acceleration of the particle, if the force \[{{F}_{1}}\] is removed?
question_answer82) A spring balance is attached to the ceiling of a lift. A man hangs his bag on the spring and the spring reads 49 N, when the lift is stationary. What will be the reading of the spring balance, if the lift moves downward with an acceleration of\[5\text{m}{{\text{s}}^{-2}}\].
question_answer83) Why does Newton's first law of motion appear to be contradicted in our day-to-day life?
question_answer84) Explain, why (a) The passengers are thrown forward from their seats, when a speeding bus stops suddenly. (b) Does a cricketer move his hand backwards while holding a catch? (c) Is the boat pushed away when a man jumps out of the boat?
question_answer85) Explain: (a) Why are ball bearings used in machinery? (b) Why does a horse have to apply more force to start a cart than to keep it moving? (c) What is the need for banking the tracks?
question_answer86) The speed of driving a car safely depends upon the range of headlight. Explain.
question_answer87) A bird is sitting on the floor of a closed glass cage and the cage is in the hand of a girl. Will the girl experience any change in the weight of the cage when the bird (i) starts flying in the cage with a constant velocity (ii) flies upwards with acceleration (iii) flies downwards with acceleration?
question_answer88) A man stands in a lift going downward with uniform velocity. He experiences a loss of weight at the start but not when lift is in uniform motion. Explain why?
question_answer89) Aeroplanes having wings fly at low altitudes while jet planes fly at high altitudes. Why?
question_answer90) A person (mass m) is hanging from a rope fastened to a stationary balloon (mass M). If the person climbs along the rope, then with what velocity the balloon will move and in what direction? The velocity of the person relative to the rope is \[\upsilon \].
question_answer91) A rope is hanging from a tree, as shown in Fig. Bananas are fastened to the higher end of the rope, and a monkey is hanging along the rope near its lower end. The monkey climbs along the rope, will it be able to eat the bananas?
question_answer92) A long rope is hanging, passing over a pulley. Two monkeys of equal weights climb up from the opposite ends of the rope. One of them climbs up more rapidly relative to rope. Which monkey will reach first at the top? The pulley is frictionless and the rope is massless and inextensible.
question_answer93) When a ball is thrown upward, its momentum first increases and then decreases. Is the conservation of momentum violated in this process?
question_answer94) A disc of mass m is placed on a table. A stiff spring is attached to it and is vertical. To the other end of the spring is attached a disc of negligible mass. What minimum force should be applied to the upper disc to press the spring such that the lower disc is lifted off the table when the external force is suddenly removed?
question_answer95) Can a single isolated force exist in nature? Give reason.
question_answer96) A body is dropped from the ceiling of a transparent cabin falling freely towards the earth. Describe the motion of the body as observed by an observer (i) sitting in the cabin (ii) standing on the earth.
question_answer97) A ball is suspended by a cord from the ceiling of a motor car. What will be the effect on the position of the ball if (i) the car is moving with uniform velocity (ii) the car is moving with accelerated motion and (iii) the car is turning towards right?
question_answer98) A block of mass M is supported by a cord C from a rigid support, and another cord D is attached to the bottom of the block. If you give a sudden jerk to D, it will break. But if you pull on D steadily, chord C will break. Why?
question_answer99) A vessel containing water is given a constant acceleration a towards the right, along a horizontal path. Which of the following figures correctly represents the surface of the liquid?
question_answer100) When brakes are applied in a bicycle, the brake shoes apply frictional force on the wheels. The forces are internal for the system (bicycle). For retardation, external forces must act on the system. The force of friction at the road surface remains the same before and after the brakes are applied\[(f=\mu R)\]. How does the bicycle stop?
question_answer101) A light string passing over a smooth pulley connects two blocks of masses \[{{m}_{1}}\] and \[{{m}_{2}}\] (vertically). If the acceleration of the system is \[g/8,\]find the ratio of the two masses.
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